Double standard in weight loss?

So I've been dating my girlfriend for almost a year, and I've told her several times that I will help her lose weight because:

1. It's healthy

2. I'm active myself ( run an hour a day+ other activity )

3. She will feel better about herself because she's wanted to lose weight

Now recently since we've both gotten our own places ( different cities, 2 hour drive ) and gotten more career oriented jobs, we're able to have a real solid schedule.

And I've been pressing some activities we can do on the weekends together.

She's become a little hostile in that she says " I want her to change ", but I think she's being a little lazy.

I asked her; " would you be okay with me if I had 50lb of fat on me? " to which she replied " honestly, no ".

And she's not fighting me too much on the issue, but it got me thinking, why is it that women ( in general ) seem to think it's bad manners and even selfish for a man to push his girlfriend to better herself physically and then it's okay to try and change a man's personality?

I never want my girlfriend to change who she is as a person, because that's what I love, but I do want her to be healthy because it's flat out better living.

P.S. She's 5"4 and 210lbs, when we met she was 200lbs. I want her to go down to 150lb which she was only 3 years ago.
Double standard in weight loss?
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